HID bulb numbers, interchange?

Hello all,
Have been looking at the posts here about replacing the HID bulbs in these cars, some get the great deals on Ebay, and different temp ratings but from what I am seeing, most of the cheaper ones are listed as "D4R-D4S" as if they interchange. It appears they do physically, except the D4R for the Prius reflector has the band on the bulb. I was wondering are the cheap bulbs people are getting on ebay and such, really the D4S without the band, and is there any noticeable difference in the performance? My 2008 has just turned over to 51K and the headlights are used daily so I am thinking I should purchase some backups and the low priced ones on Ebay do look inviting, but the bulbs pictured don't have the band, and in fact some even list along with the "R" and "S",a "C" in the number.

Hoping someone can shed light on this, and I did search but didn't find anything on this.

Thanks,

John

 

Wow, now that does worry me. But you say you bought D4R, I don't think that's what they sent you as the "R" should have the band on it. I have read on other forums that some of the cheapy bulbs have had their sockets swapped so you may not be getting what you were supposed to but I would think, that if it were at D4S it should electrically work..I wonder why yours isn't working? I wonder if they put a D2S bulb on a D4R socket? Please post back with whatever your solution is.

Am trying to be really careful to get the right thing, don't need em yet but don't want to wait until I do.

John

 

BUMP-
Nobody? I just knew someone would have run across this bulb number issue and could share with us....

John